> That being said, anyone who’s operated a two-sided marketplace knows that one of the biggest problems is consumers using your site as an index, and then seeking to dodge your fee by meeting with the seller on another platform, where they don’t have to pay it.

There is a company that operates an index where people can search for things and doesn't charge the site or the customer for things that rank well in organic search results. I think they're called Google. From what I understand they make quite a bit of money by selling ads next to the listings.

That model seems like it would work pretty well for such a platform, unless there was some major company preventing anyone from offering a lower price than they have on their own site so that everybody goes to their site instead of using a price search engine to find a site with a lower price.

I mean come on. If they're really using your site just to find a product, you think that's a problem?

Meanwhile a platform's fee should be going to things like payment processing, warehousing and shipping, and then if you're offering a competitive price for those services they should want to be paying you because they need those things and can't get a better deal on them somewhere else. If they can get a better deal on them and are only using your site because you're forcing them to with a dirty trick, maybe they're right to object?